Lifting-jack.



FRANK L. GORMLEY, OF BOSTON, MASSACHUSETTS.

LIFTING-JAGK.

Specification of Letters Patent.

Patented Sept. 7, 1909.

Application filed February 15, 1909. Serial No. 478,306.

To all whom it may concern:

Be it known that I, FRANK L. GORMLEY, a citizen of the United States ofAmerica, and a resident of Boston, in the county of Suffolk and State ofMassachusetts, have invented certain new and useful Improvements inLifting-Jacks, of which the following is a specification.

This invention relates to lifting jacks and particularly to that classof jacks which are known as ratchet screw jacks, and has for its objectthe provision of a means whereby the movable member is prevented frombeing accidentally lowered under a heavy load.

The invention consists in providing the upper end of the screw memberwith a toothed disk with the teeth of which is adapted to engage a pawlpivotally mounted in an annular plate freely revoluble upon the gear forrotating said screw, a friction disk being interposed between saidannular plate and the movable member of said lifting jack. Thisconstruction provides a means whereby during the raising of the movablemember the screw with the disk secured thereto is freely rotatedindependently of the annular plate surrounding said disk but when theraising of'the movable member ceases and the weight of the load uponsaid movable member tends to move the screw downwardly in its nut on thestationary member, the pawl interposed between said annular plate anddisk will engage the teeth of the latter and cause the two members tomove simultaneously and owing to the friction between the contactingsurfaces of the annular plate and the inner face of the mov able memberthe disk on the screw will be either locked and prevented from moving orwill move under considerable difficulty, thus preventing the movablemember from being accidentally lowered.

The invention consists in certain novel features of construction andarrangement of parts which will be readily understood by reference tothe description of the drawings and to the claims hereinafter given.

Of the drawings: Figure 1 represents a vertical section of a liftingjack embodying the features of this invention, the cutting plane beingon line 1-1 on Fig. 2. Fig. 2 represents a horizontal section of thesame, the cutting plane being on line 22 on Fig. 1, and Fig. 3represents a vertical section of the screw operating mechanism,.thecutting plane being on line 3-3 on Fig. 2.

Similar characters designate like parts throughout the several figuresof the drawings.

In the drawings, 10 represents a suitable base supporting a stationarystandard 11 over the outer periphery of which is fitted a movable sleeve12, to the upper end of which is threaded a head 13. In the upper end ofthe head 13 is mounted a plate 14 provided with an annular groove 15.Between the plate 14 and the inner face of the head 13 is interposed afriction disk 16. The standard 11 is provided with a nut 17 to which isthreaded a screw 18, to the reduced upper end of which is splined a gear19 having an annular groove 20 in the upper face thereof in which ismounted a plurality of anti-friction members 21, the upper portions ofwhich project into the annular groove 15 of the annular plate 14, thuspermitting the annular plate 14 to be freely revoluble about the aXis ofthe screw 18 on said anti-friction members 21. 4

To the squared end 22 of the screw member 18 is secured a disk 23provided with a plurality of ratchet teeth 24 with which engage the pawlmembers 25 mounted in depressions in the annular plate 14 and forcedinto engagement with the teeth 24 of said disk 23 by means of thesprings 26, all as in dicated in Figs. land 2.

The gear 19 meshes with a gear 27 formed upon or secured to.a revolubleshaft 28 to the reduced end of which is keyed or otherwise secured aratchet 29, between the two arms 30 of a bifurcated member 31. Thisbifurcated member 31 is provided with an operating handle 32 and in ears33 formed upon the arms 30 is secured a pin 34 upon which is mounted thedouble acting pawl 35, one of the teeth of which is retained inengagement with the teeth of the ratchet 29 by means of the locking bolt36 mounted in a socket in the member 31 and forced outwardly by means ofthe spring 37. The bolt 36 is prevented from turning by means of thescrew 38 engaging a longitudinal slot in the bolt 36, as indicated inFig. 3, and the outer end of said bolt is V-shaped so that the pointthereof will engage either the face 39 of the pawl to cause one of theteeth thereof to engage with the ratchet wheel 29 or with the face 40 tocause the other tooth of the pawl to engage with the ratchet wheel, theparticular tooth to be engaged with the ratchet wheel 29 beingdetermined by the direction in which it is desired to turn the gear 27.

It is obvious that by giving thehandle 32 an up and down or pump handlemotion with the pawl 35 in the position shown'in Fig. 3, the gears 19and 27 will be rotated so as to cause the screw 18 to turn within.

the nut 17 to cause a lifting of the head 13 relative to the standard11. It is also obvious that when the position of the doubleacting pawl35 is reversed and the V-shaped end of the locking bolt 36 is inengagement with the face 39 of said pawl and the same motion is accordedto the handle 32 a reverse motion will be accorded to the gears 19 and27 and the screw 18 will be turned in its nut 17 to cause a lowering ofthe head 13. WVhen the handle 32 is operated to cause a lifting of themember 13 the toothed disk 23 turns freely in the direction of the arrowindicated thereon in Fig. 2 of the drawings without necessarily movingthe annular plate 14 which surrounds said disk, this disk 14 beingprevented from movement with the disk 23 by means of the friction disk16 interposed between the same and the upper end of the member 13.

When the threads of the screw 18 are of a certain coarse pitch and thehead 13 is subjected to the weight of a heavy load,

1 sometimes the screw 18 would turn in the nut 17 and cause theaccidental lowering of the head relative to the standard 11 if somedevice was not provided to prevent this action which is dangerous andobviously objectionable. By the devices shown and described, however,this objection is entirely overcome as when the screw begins to turn inthe reverse direction the teeth 24 on the disk 23 will come intoengagement with the pawls 25 and tend to cause the annular plate 14 torevolve therewith. The friction, however, between this annular plate andthe movable member 13 due to theinterposition of the friction disk 16between said plate 14 and member 13 will wholly prevent the rotation ofthe screw 18 in the nut 17 and the consequent lowering of the member 13or will so limit it as to prevent any accident from occurring. I

It is obvious that during the lifting of the member 13 the toothed disk23 is free to revolve with the screw 18 independently of thepawl-carrying plate 14 surrounding the same, this plate being preventedfrom movement with the disk by the contact between it and the inner faceof the end of the movable member 13. As soon, however, as the head 13 issubjected to a heavy load the weight of which is suflicient to cause atendency of the screw 18 to accidentally rotate in the nut 17, therotation of the screw 14 will cause the teeth of the disk 23 to engagewith the pawls 25 in the annular plate 14 and oblige this annular plateto rotate therewith, overcoming the friction between the plate and themember 13, or if this friction is in excess of the weight upon themember 13 theannular plate 14 will not rotate with inthe member 13 butwill obviously prevent the rotation of the screw 18, thus preventing thelowering of the member 13.

It is believed that the operation and many advantages of the inventionwill be fully understood from the'forego'ing description.

Having thus described my invention, I claim:

1. In a lifting jack, the combination of a stationary member; a movablemember thereon; a screw for said movable member; means for rotating saidscrew; an annular plate interposed between said screw rotating means andsaid movable member; and means interposed between SELlCl'iLIlIlLIlZLIplate and screw adapted to connect them and insure the snnultaneousrotation of said plate and screw 111 one d1rect1on and to disconnectthem to permit independent movement of.

said screw in the opposite direction.

2. In alifting jack, the combination of a stationary member; a' movablemember thereon; a screw for said movable member;

a gear for rotating said screw; an annular 7 stationary member; amovable member" thereon; a screw for said movable member;

a gear for rotating said screw; an annular plate on said gear; a disksecured to said screw; means interposed between said disk and annularplate adapted to disconnect them during the rotation'of said screwin onedirection to permit said screw to rotate independently of said plate andto connect them in the rotation of the screw in the opposite directionto insure the simultaneous movement of said plate and screw; and afriction disk between said plate and movable member.

4. In a lifting jack, the combination of a stationary member; a movablemember thereon; a screw for said movable member; a gear for rotatingsaid screw; a disk secured to said screw provided with a plurality ofratchet teeth; and an annular plate on said gear provided with a pawlengaging said ratchet teeth. 7

5. In a lifting jack, the combination of a stationary member; a movablemember thereon; a screw for said movable member; a gear for .rotatingsaid screw; a disk secured to said screw provided with a plurality ofratchet teeth; and an annular plate on said gear provided with aspring-pressed pawl engaging said ratchet teeth.

6. In a lifting jack, the combination of a stationary member; a movablemember thereon; a screw for said movable member; a gear on said screw; aplate member on said gear; a disk member secured to said screw; and apawl pivotally secured to one of said members and adapted to engageteeth formed upon the other member, thus insuring the simultaneousrotation of said disk member and plate member in one direction whilepermitting independent movement of said screw in the opposite direction.

7 In a lifting jack, the combination of a stationary member; a movablemember thereon; a screw for said movable member; a gear on said screw; aplate member on said gear; a disk member secured to said screw; a pawlpivotally secured to one of said members and adapted to engage teethformed upon the other member, thus insuring the simultaneous rotation ofsaid disk member and plate member in one direction while permittingindependent movement of said disk member in the opposite direction; anda plurality of anti-friction members interposed between said plate andgear.

8. In a lifting jack, the combination of a stationary member; a movablemember thereon; a screw for said movable member; a gear on said screw; aplate member on said gear; a disk member secured to said screw; a pawlpivotally secured to one of said members and adapted to engage teethformed upon the other member, thus insuring the simultaneous rotation ofsaid disk member and plate member in one direction while permittingindependent movement of said disk member in the opposite direction; anda friction disk interposed between said movable member and said annularplate.

Signed by me at 4 Post Oflice Sq., Boston, Mass, this 28th day ofJanuary, 1909.

FRANK L. GORMLEY.

Witnesses EDNA C. CLEVELAND; WALTER E. LOMBARD.

